Interferometers are useful for measuring optical properties of materials, such as the refractive index. Some interferometers include a large number of reflectors, which can be bulky and difficult to maintain in alignment. For example, a conventional Mach Zehnder interferometer includes a light source, a beamsplitter, two steering mirrors, a second beamsplitter that operates as a beam combiner, and a detector.
Therefore, there is a need for an interferometer that is easy to maintain in alignment and can be made to be compact.